Fabrication of submicron- or nano-sized mesa electrodes via AFM oxidation: Applications to metal ion detection

Conductive probe AFM local oxidation is a promising lithographic technique for use in fabricating submicron- or nano-scale structures. In this study, a metal ion detector with a submicron size electrode was fabricated by AFM lithography using a pre-programmed voltage and a non-etching method. The square frame of the mesa pattern was functionalized by APTES for the metal ion detection, and the remaining portion was used as an electrode by the self-assembly of MPTMS for Au metal deposition. In this module, no metal lining or lead line was required, because the conductive tip (mobile electrode) was in direct contact with the gold-deposited mesa portion (fixed electrode). The conductance changed with the quantity of adsorbed copper ions, due to electron tunneling between the mobile and surface electrodes.